n = int(input())

empty=[]

i = 0
for _ in range(n):
    [a,b,c] =[int(i) for i in input().split(' ')]
    empty.append(a)
    empty.append(b)
    empty.append(c)

empty=sorted(empty)

items=[1,2,3,4,5,6,7,8,9,10]

i=0
j=0
for p in items:
    empty.count(p)
    if empty.count(p)>=2:
        i+= empty.count(p)//2
    if empty.count(p)%2==1:
        j+=1

print(i+j//4)